To the Editor:
—Recently accumulating data that cast serious doubt on the association of adenomatous polyps and the development of rectal carcinoma should not be misinterpreted as negating the importance of sigmoidoscopy. It would be useful to have some characteristic to identify the cancer-prone patients who require more careful observations. Adenomatous polyps apparently do not fulfill this role. Thus, patients without polyps should have the same periodic re-examinations that previously were suggested for polyp-bearers, until better indices of increased cancer risk are defined.There does not appear to be any substantive difference of opinion between Dr. Roberts' comment and the editorial.